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Lubricants It is known to use blended polymers composed of methyl polysiloxane segments and polyether or polyolefin segments for lubrication of sliding metal surfaces.

However, these lubricants have for many applications the disadvantage that they are either insoluble in water because of their longer carbon chains or, as far as they are water soluble thanks to suitable polyether chains, these chains bonded via hydrolyzable Si - 0 - C bridges to the polysiloxane chains and therefore against Water are not stable.

This disadvantage is avoided if alkylene oxide-methylsiloxane polymers whose units contain from 10 to 25% by weight of (CHg) 2SiO, optionally to 3% by weight of CH3SiO312 and optionally to 5% by weight of (CH3) 3SiOli2, and to 70 to 80% by weight of those of the formula RO ( - R'O -) CH 2 --Si (CH 3) 2 O, 12 where R is a hydrogen atom or a lower alkyl radical and (R'O) n is a polyalkylene oxide chain having a molecular weight between 500 and 2500, consisting of 30 to 60 weight percent of ethylene oxide, 30 to 60 weight percent of propylene oxide and up to 30 weight percent butylene oxide, means optionally used in admixture with water, hydrophilic organic liquids or thickeners as a lubricant.

The molecular weight of these methyl (organooxymethyl) siloxanes is more than 1000. They may be low-viscosity or viscous oils with low pour points or of a fat-like consistency. The viscosity of the oils is only slightly dependent on the temperature. According to German Patent 1,195,553, this compound can be prepared by reacting a bromine-substituted methylpolysiloxane consisting of 40 to 80 parts by weight of (CH3) 2SiO and 8 to 40 parts by weight of BrCH2Si (CH3) 2O, 12 optionally to 10 parts by weight of CH3SiO312 and optionally to 15 Parts by weight of (CH3) 3SiOls2, reacting with a polyether alcohol of the formula RO (R'O) n H and a tertiary nitrogen base at a temperature above 50 ° C., in that for each gram atom of bromine at least one gram equivalent of the polyether alcohol and of the nitrogen base is used and the course of the reaction is conducted so that at any time the amount of nitrogen base fed to the bromine compound in the reaction mixture is at most equal to the amount of polyether alcohol previously charged to the bromo compound.

The compounds to be used according to the invention give excellent lubricating action and also in the area of ​​the boundary friction between two steel surfaces very low frictional forces, as the known test method on the Almen-Wieland machine proves. Moreover, without the risk of hydrolytic changes, they are compatible with water and hydrophilic organic liquids and can be used in admixture with those for lubrication, in particular in metal-cutting operations. Even small amounts are sufficient in aqueous solution to achieve a good lubricating film load-bearing capacity, as can be demonstrated by testing on the friction wear scale after R eichert. For this test method cf. »Arbeitskreis Schrifttumsauswertung Schmierstoffe«, Report No. 267 (1957), pp. 1 to 3, C adme r.

For the mentioned hydrophilic organic liquids come z. For example, ethylene glycol, diethylene glycol, triethylene glycol, dimethylformamide, methyl ethyl ketone and polyether, as z. B. by polymerization of Alkylenoxyden, by polycondensation of glycols, by reacting glycols with aliphatic dihalogeno or by reacting monohydric or polyhydric alcohols or mercaptans with Alkylenoxyden are available.

The methyl (organooxymethyl) siloxanes to be used according to the invention can be mixed with known antioxidants, corrosion inhibitors and defoaming agents and pastes and greases can be produced therefrom by means of conventional thickening agents.

Both the use of polyethers and of esterification products of polyether alcohols and hydroxysiloxanes as lubricants are known. The lubricants according to the invention, however, far exceed the polyethers and to a lesser extent also the mentioned esterification products in their lubricating effect. Compared with the latter, however, they are distinguished above all by the fact that their proportion of siloxane with the polyether portion is not linked via the hydrolytically cleavable Si - O - C bridge, but via the ether bridge Si C 0 - C, so that it can be safely used in aqueous systems are.

In the following compilation of tests found in the Almen-Wieland machine werder compared: 1. The mono-n-butyl ether RO (R'O -) n H a composed of ethylene oxide and propylene oxide in equal parts by weight poly alkylene glycol of the OH number 35th

2. An esterification product of 3 parts by weight of the same polyglycol monoether and 1 part by weight of a trifunctional and difunctional units methylpolysiloxane of the composition [CH 2 SiO 3 12] [(CH 3) 2 SiO] 17 [RO (R'O) - n Si (CH 3) 20112] 3 3. An etherification product according to the invention of 3 parts by weight of the same polyglycol monoether as in 1 and 2 and a polysiloxane of analogous structure as under 2 of the composition [CH 3 SiO 3,21 [(CH 3) 2 SiO] 17 [RO (R'O) n CH 2 Si (CH 3) 2011 2] a <p><p><tgroup cols="1"><tbody><row><entry align="right">111213</entry></row><row><entry align="right">MaximalerAnpreßdruck</entry></row><row><entry align="right">from seizing the</entry></row><row><entry align="right">Warehouse, kg. , , , , , , , , 850 1800 1900</entry></row><row><entry align="right">Frictional force, kg 165 290 220</entry></row><row><entry align="right">Attrition, kg ...... 0.03 0.11 0.10</entry></row><row><entry align="right">Temperature, ° C 50 73 61</entry></row></tbody></tgroup></p></p>